It would depend on a few factors:
1) Whether I really needed an answer to that question- if it isn't going to help with anything then there is no point being hurt for no reason.
2) Whether I was feeling strong enough to safely deal and cope with the hurt of the answer
3) What I would do when I had the answer.
4) How I thought having that answer would affect my relationship with that person
It sounds like you may already have an idea what the answer is to the question without even asking it but hearing it from another person may make it clearer I suppose. In some ways I think you are lucky to have someone that you trust to tell you the 100% truth. Whatever you decide to do I hope it gives you what you are looking for.
Erm why ask the question in the first place if you know the answer?
~Phoenix~ is my Little Sister of Awesomeness and Self-Delusion :P Bitter Angel is my Mitten Animad is my Top Trump All Im Living For - Is my beautiful and special daughter who isnt called Kim but will moan if i dont add her :P
Because that niggle of doubt that it wasn't what I thought it was would eat away at me. And it's better to have it completely confirmed so you can get over it or whatever you need to do than always have that little thing eating away at you.